Karl Stefanovic's ex to sizzle on Dancing with the Stars

Cassandra Thorburn has made her revenge move with Karl Stefanovic's ex wife confirming she will compete on Dancing With The Stars.

Despite previously asking for privacy, the mother of three will hit the dance floor on the revamped reality show.

"Once we get into learning the choreography of something and going over and over that dance, that is going to get physically demanding," Thorburn said, adding of her fitness level: "I have lots of stairs at my house, like a lot of stairs. I have like 96 stairs to get to my house so I'm up and down those a lot."

Stefanovic married new partner, fashion designer Jasmine Yarbrough, in Mexico in December, days before he was sacked from his high profile hosting job on Nine's struggling breakfast show, Today.

For now though, former journalist Thorburn's focus is on dancing as she'll go head to head with celebrities including actor Samuel Johnson and former West Indies cricketer Curtly Ambrose.

"I decided to do it because it was one of the last conversations I had with my dad before he passed away," she said.

"It had been offered to me and at first I thought, no that's crazy. I couldn't possibly do that. If you don't do something, an opportunity that you never thought would come up and if you said no … you will regret it one day.

"And I thought 'OK so let's go for it'. Plus learning to dance, you know every girl would love to learn to dance. It is so lovely, what a skill."